that's easy to understand from sort of an engineering perspective.

从工程学的观点看这很好理解
You produce this ultra-filtrate, and then the kidney works very hard

你产生超滤液然后肾脏拼命帮你
to recover the molecules that you need

把你所需的分子再拣回来
so that you don't have to produce a large volume of urine

因此你不必通过产生大量的尿液
in order to get rid of the waste.

来排泄废物
It does that by two processes, reabsorption and secretion,

通过两个过程来实现该功能重吸收和排泌
which I've already mentioned, and we're really going to focus mainly on

我已经提到过了今天剩下的时间
reabsorption for the rest of the time here today.

我们集中讨论下重吸收
In reabsorption the key elements of reabsorption

重吸收中的关键是
are reabsorption of water or return of much of this volume of water

水的重吸收或者说将大部分在肾小球中
that's filtered at the glomerulus and recovery of solutes

过滤出来的水再退回去并恢复所需的溶质
that are needed like sodium and potassium and bicarbonate.

像钠钾和碳酸氢盐